AvroTraits.hh

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 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#ifndef avro_AvroTraits_hh__
#define avro_AvroTraits_hh__
 
#include "Config.hh"
#include "Types.hh"
#include <cstdint>
#include <type_traits>
 
namespace avro {
 
template<typename T>
struct is_serializable : public std::false_type {};
 
template<typename T>
struct is_promotable : public std::false_type {};
 
template<typename T>
struct type_to_avro {
    static const Type type = AVRO_NUM_TYPES;
};
 
template<class T>
struct is_defined {
 
    typedef char yes[1];
 
    typedef char no[2];
 
    template<class U>
    static yes &test(char (*)[sizeof(U)]) { throw 0; }
 
    template<class U>
    static no &test(...) { throw 0; }
 
    static const bool value = sizeof(test<T>(0)) == sizeof(yes);
};
 
template<class T>
struct is_not_defined {
 
    typedef char yes[1];
 
    typedef char no[2];
 
    template<class U>
    static yes &test(char (*)[sizeof(U)]) { throw 0; }
 
    template<class U>
    static no &test(...) { throw 0; }
 
    static const bool value = sizeof(test<T>(0)) == sizeof(no);
};
 
#define DEFINE_PRIMITIVE(CTYPE, AVROTYPE)                     \
    template<>                                                \
    struct is_serializable<CTYPE> : public std::true_type {}; \
                                                              \
    template<>                                                \
    struct type_to_avro<CTYPE> {                              \
        static const Type type = AVROTYPE;                    \
    };
 
#define DEFINE_PROMOTABLE_PRIMITIVE(CTYPE, AVROTYPE)        \
    template<>                                              \
    struct is_promotable<CTYPE> : public std::true_type {}; \
                                                            \
    DEFINE_PRIMITIVE(CTYPE, AVROTYPE)
 
DEFINE_PROMOTABLE_PRIMITIVE(int32_t, AVRO_INT)
DEFINE_PROMOTABLE_PRIMITIVE(int64_t, AVRO_LONG)
DEFINE_PROMOTABLE_PRIMITIVE(float, AVRO_FLOAT)
DEFINE_PRIMITIVE(double, AVRO_DOUBLE)
DEFINE_PRIMITIVE(bool, AVRO_BOOL)
DEFINE_PRIMITIVE(Null, AVRO_NULL)
DEFINE_PRIMITIVE(std::string, AVRO_STRING)
DEFINE_PRIMITIVE(std::vector<uint8_t>, AVRO_BYTES)
 
} // namespace avro
 
#endif